The present disclosure relates generally to a diamine adhesion enhancer. In particular, the disclosure is related to cycloaliphatic diamines as adhesion enhancers. More particularly, the disclosure relates to cycloaliphatic diamines as adhesion enhancers between polyolefinic or ionomeric substrates and urethane substrates.
Golf balls are important sporting goods that have changed with changes in technology. For example, balls were first made of wood, and then by stuffing boiled, softened feathers into a leather sack. The sack typically was painted white, and would tighten upon drying. However, because the feather ball tended to absorb moisture and to split, many balls were required to play a round. Also, these feather balls were expensive as compared with wooden balls.
Both feather and wooden balls were in use until the gutta percha ball was made. The gutta percha ball was relatively inexpensive and easily manufactured. Also, the gutta percha ball was fairly durable, as compared with the feather ball, performed well because the surface could easily be roughened to improve flight characteristics, and so became popular. However, the ball exhibited a tendency to break up in flight.
Golf balls comprising other elastic materials then were developed. For example, a golf ball having a rubber core and an elastic thread wound tightly around the core was developed. The winding was covered with gun percha at first, but later with balata. However, balata-covered golf balls often are damaged by players who are less skilled at striking the ball. Thus, tougher covers were developed, including in particular covers comprising a Surlyn® compound or a polyurethane compound.
The interior structure of the golf ball also has advanced, with plastics and polymeric materials having properties and characteristics appropriate for manufacture of high-quality, high-performance, affordable golf balls. In particular, polymeric materials having properties and characteristics appropriate for golf ball manufacture have been developed. Such polymeric materials include polyurethanes and polyolefinic or ionomeric materials, including neutralized acid polymers. Blended materials also are used to manufacture other products.
Often, these various materials are formed into separate layers of a golf ball, with each successive layer essentially surrounding the previous layer. The skilled practitioner recognizes that, typically, the layers must adhere to each other for the golf ball to perform to desired specifications and to be durable. However, many layer combinations that manufacturers seek to make are difficult, if not impossible, to make successfully because interlayer adhesion is poor between dissimilar polymers. In particular, polyolefinic and ionomeric materials do not adhere well to polyurethane materials. However, polyolefinic and ionomeric materials have properties and characteristics that make them especially suitable for interior layers of golf balls, and polyurethane materials can be used to make high-performance, durable covers for golf balls. Thus, the ability to make this bond between an ionomeric material and a polyurethane material can be important.
Therefore, there exists in the art a need for a mechanism by which the bonding between a golf ball layer comprising a polymeric material or ionomeric material and an adjacent layer comprising a polyurethane material can be increased.